Highly viscous, water separable conductive adhesive and method of making same

Abstract

The application discloses a kind of high viscosity, water separable conductive glue and preparation method thereof, belong to conductive glue material technical field, the application uses mixed grinding preparation conductive glue by heteropoly acid, aromatic amino acid containing phenolic hydroxyl group and conductive component.The selection of amino acid in the application has uniqueness, it needs to meet with phenolic hydroxyl group and has certain hydrophobicity;The reaction of the application can be carried out at room temperature, without solvent, avoid the pollution caused to environment due to using a large amount of solvent;The application can effectively solve the problem that the metal salt and its oxide with strong hydrophobicity and poor solubility cannot react in aqueous solution by solid phase polymerization;The conductive glue prepared by the application can be immediately debonded after contacting water, realizes on-demand separation, can be recycled and reused after absorbing certain moisture, and the recycling mode is simple to operate, environmental protection, reduces cost.

Description

Technical Field

[0001] This invention relates to the field of conductive adhesive materials technology, and more specifically to a high-viscosity, water-separable conductive adhesive and its preparation method. Background Technology

[0002] Conductive adhesives possess a dual function: they conduct electricity and form mechanical bonds between various substrates, thus finding wide application in electronic skin, strain sensors, and other electronic products [C.Mu, X.Wang, Z.Ma, X.Liu and W.Li, J.Mater.Chem.A, 2022, 10, 7207]. Generally, the most important characteristic of conductive adhesives is their adhesive strength, which determines the reliability and durability of device assembly. However, during repair or fabrication processes, it is also necessary to easily separate the adhesive without damaging the bonded components to enable component reuse. Therefore, there is an increasing need to develop separable conductive adhesives with high adhesive strength.

[0003] Currently, some progress has been made in achieving non-destructive separation of separable conductive adhesives. Developed separable conductive adhesives are mainly based on stimulus-responsive materials, such as thermally and photoresponsive polymers [Wang.Z,Guo.L,Xiao.H,Cong.H,Wang.S.,Mater.Horiz.2020,7,282-288;Zhao.R,Mu.J,Bai.J,Zhao.W,Gong.P,Chen.L,Zhang.N,Shang.X,Liu.F;Yan.S.,ACS Appl.Mater.Interfaces 2022,14,16678-16686]. The main focus of these stimulus-responsive separable conductive adhesives is the disruption of chemical bonds and the phase transition or topological transformation of the polymer; therefore, a strong exfoliation process is required, such as prolonged high-temperature heating or prolonged ultraviolet irradiation. For example, adhesives prepared by Liu et al. and Xi et al. by introducing high-melting-point ionic liquids (also known as ionic crystals) into polymers exhibit high adhesive strength [Liu.L,Liu.Z,Ren.Y,Zou.X,Peng.W,Li.W,Wu.Y,Zheng.S,Wang.X,Yan.F.,Angew.Chem.2021,133,9030-9041;Xi.S,Tian.F,Wei.G,He.X,Shang.Y,Ju.Y,Li.W,Lu.Q,Wang.Q.,Adv.Mater.2021,33,2103174]. The phase transition of the ionic crystals allows the adhesives to separate after heating at 80 or 120 °C for 10 minutes. Yan et al. prepared a phototriggered, peelable conductive adhesive by incorporating carbon black into an ionic crystal gel [L.Liu,Z.Liu,Y.Ren,X.Zou,W.Peng,W.Li,Y.Wu,S.Zheng,X.Wang,F.Yan.,Angew.Chem.Int.Ed.,2021,60,8948-8959]. The lap shear strength of the photothermal ionic crystal conductive adhesive can reversibly change with the melting and crystallization of the ionic crystal. It is important to note that prolonged high-temperature heating may cause irreversible damage to the bonded components. Besides heating, other harsh triggering factors such as immersion in organic solvents and ultraviolet irradiation have also been used for the separation of conductive adhesives. However, these methods are typically energy-intensive, time-consuming, and can damage devices, and also pose environmental problems.

[0004] Currently, a major challenge in manufacturing separable conductive adhesives lies in how to achieve a convenient switch between strong adhesive and non-adhesive states through mild triggering conditions. Therefore, providing a mild, simple, and feasible strategy to prepare separable conductive adhesives with high adhesive strength is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a conductive adhesive with high adhesive strength but water separability, constructed using a solid-phase supramolecular polymerization strategy, comprising aromatic amino acids containing phenolic hydroxyl groups, heteropoly acids, and conductive components. The adhesive constructed using this solid-phase polymerization strategy has unique requirements for the selection of amino acids; it must possess both phenolic hydroxyl groups and a certain degree of hydrophobicity, both of which are indispensable.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A highly viscous, water-separable conductive adhesive comprises the following raw materials by mass percentage: 83%–87% heteropolyacids, 16%–21% aromatic amino acids containing phenolic hydroxyl groups, and the balance being conductive components.

[0008] In the technical solution of this invention, heteropolyacids serve as crosslinking agents, and aromatic amino acids containing phenolic hydroxyl groups, along with conductive components, form a crosslinked three-dimensional network structure through solid-phase supramolecular polymerization. The resulting viscous conductive adhesive has an internal morphology consisting of a three-dimensional crosslinked structure formed by aromatic amino acids containing phenolic hydroxyl groups, heteropolyacids, and conductive components through electrostatic interactions, hydrogen bonding, charge transfer, and coordination. When the constructed conductive adhesive comes into contact with water, its adhesion immediately decreases, allowing for easy separation.

[0009] Furthermore, the heteropolyacid is H3PW. 12 O 40 (PW), H3PMo 12 O 40 (PMO), H4SiW 12 O 40 (SiW), H6P2W 18 O 62 (HP2W 18 Any one of them.

[0010] Furthermore, the aromatic amino acid containing the phenolic hydroxyl group is tyrosine (Y) and / or levodopa (DOPA).

[0011] Furthermore, the conductive component is liquid metal (LM).

[0012] This invention also provides a method for preparing the above-mentioned high-viscosity, water-separable conductive adhesive, comprising the following steps:

[0013] (1) Weigh each raw material according to the above mass percentages;

[0014] (2) Mix and grind aromatic amino acids containing phenolic hydroxyl groups, heteropoly acids and conductive components for 3-5 minutes to form a conductive adhesive with low viscosity;

[0015] (3) Continue grinding the mixture for 3 to 5 minutes to form a conductive adhesive with high viscosity;

[0016] Furthermore, steps (2) and (3) are carried out under conditions of 60% humidity.

[0017] The beneficial effects of this invention are as follows: This invention uses aromatic amino acids containing phenolic hydroxyl groups as raw materials and employs solid-state polymerization to construct a conductive adhesive with a cross-linked three-dimensional network structure, incorporating polymetallic oxygen clusters and conductive components. During solid-state grinding, the aromatic amino acids containing phenolic hydroxyl groups, heteropolyacids, and conductive components form a stable cross-linked network through electrostatic interactions, hydrogen bonding, charge transfer, and coordination. Its reversible multi-electron redox properties act as an electron sponge, accepting and donating electrons. The adhesive groups (amino, carboxyl, etc.) on the aromatic amino acids containing phenolic hydroxyl groups give the conductive adhesive excellent interfacial adhesion, while the conductive components accelerate electron transfer. The dynamic cross-linked network formed between the heteropolyacids and the aromatic amino acids containing phenolic hydroxyl groups in the conductive adhesive endows it with processability and deformability.

[0018] The present invention provides a convenient and mild process for preparing an adhesive conductive adhesive composed of aromatic amino acids containing phenolic hydroxyl groups, heteropoly acids, and conductive components. In particular, the reaction can be carried out under solvent-free conditions, avoiding environmental pollution caused by the use of large amounts of solvents, making it environmentally friendly. Furthermore, the solid-phase polymerization strategy effectively solves the problem that highly hydrophobic and poorly soluble metal salts and their oxides cannot react in aqueous solutions. The resulting conductive adhesive debinds immediately upon contact with water, allowing for on-demand separation. After absorbing a certain amount of moisture, it can be recycled and reused. The recycling method is simple, environmentally friendly, and reduces costs.

[0019] The advantages of this invention in preparing a highly viscous yet water-separable conductive adhesive using a solid-phase supramolecular polymerization strategy are:

[0020] 1) The selection of amino acids is unique, and they must meet the requirements of having phenolic hydroxyl groups and having a certain degree of hydrophobicity. Both of these are indispensable.

[0021] 2) Green and environmentally friendly, the reaction can be carried out at room temperature and under solvent-free conditions, avoiding environmental pollution caused by the use of large amounts of solvent;

[0022] 3) Solid-state polymerization can effectively solve the problem that metal salts and their oxides, which are highly hydrophobic and poorly soluble, cannot react in aqueous solutions.

[0023] 4) The resulting conductive adhesive can immediately detach from water, achieving separation as needed. After absorbing a certain amount of moisture, it can be recycled and reused. The recycling method is simple to operate, environmentally friendly, and reduces costs. Attached Figure Description

[0024] Figure 1The images are digital photographs of the conductive adhesive PW / Y / LM after solid-phase grinding for 3 and 9 minutes respectively at 60% humidity in Example 1 of this invention.

[0025] Figure 2 This is a digital photograph of amino acids without phenolic hydroxyl groups, or highly hydrophobic amino acids, heteropoly acids, and liquid metal after grinding under solid-phase grinding conditions of 60% humidity for 3-10 minutes, as described in Example 1 of this invention.

[0026] Figure 3 This is a digital photograph of DOPA (with two phenolic hydroxyl groups), heteropoly acid, and liquid metal after grinding under solid-phase grinding conditions of 60% humidity for 3-10 minutes, as described in Example 1 of the present invention.

[0027] Figure 4 This is a bar graph showing the energy storage modulus of conductive adhesive PW / Y / LM under solid-state grinding conditions of 60% humidity for 3, 5, 7, 9, and 10 minutes, respectively, in Example 1 of the present invention.

[0028] Figure 5 This is a bar graph showing the shear tensile strength of the conductive adhesive PW / Y / LM bonded to the solid titanium substrate under solid-phase grinding for 3, 5, 7, 9, and 10 minutes at 60% humidity in Example 1 of the present invention.

[0029] Figure 6 XPS curves of conductive adhesive PW / Y / LM under solid-phase grinding for 3, 5, 7, 9, and 10 minutes at 60% humidity in Example 1 of this invention.

[0030] Figure 7 The conductivity diagram of conductive adhesive PW / Y / LM in Example 1 of the present invention is shown in the figure. The conductivity diagram is shown in the figure.

[0031] Figure 8 A digital photograph of the conductive adhesive of this invention placed in a glass bottle containing 3 mL of secondary water.

[0032] Figure 9 This is a digital photograph of the reusable conductive adhesive of the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] (1) Preparation of viscous heteropolyacid conductive adhesive PW / Y / LM

[0036] At 60% humidity, white powders PW (0.529 g), Y (0.100 g), and liquid metal (0.012 g) were ground in an agate mortar for 3 minutes to form a low-viscosity PW / Y / LM mixture. Figure 1 a) Continue grinding for 6 minutes to form a highly viscous adhesive, such as Figure 1 b. At this point, the molar ratio of PW to Y remains at 1:3. PW acts as a crosslinking agent, Y as a building block, and LM as a conductive component, forming a crosslinked three-dimensional network structure through solid-state polymerization.

[0037] Figure 1 These are digital photographs of the conductive adhesive PW / Y / LM under solid-phase grinding conditions of 60% humidity and 3 and 9 minutes. The images show that the viscosity of the conductive adhesive PW / Y / LM is relatively low after 3 minutes of solid-phase grinding. As grinding continues for several more minutes, the viscosity gradually increases, suggesting that the conductive adhesive PW / Y / LM underwent curing during solid-phase supramolecular polymerization.

[0038] (2) The uniqueness of amino acids in viscous heteropolyacid conductive adhesives:

[0039] Further evidence demonstrates the unique selection of amino acids for adhesives constructed using solid-phase polymerization. As a comparative experiment, amino acids without phenolic hydroxyl groups or with strong hydrophobicity were selected and thoroughly ground with PW and liquid metal under 60% humidity conditions (solid-phase grinding for 3–10 minutes), and the observed phenomena were observed. Subsequently, levodopa (DOPA), containing two phenolic hydroxyl groups, was thoroughly ground with PW and liquid metal under the same conditions (solid-phase grinding for 3–10 minutes), and the observed phenomena were also observed.

[0040] Appendix Figure 2 These are digital photographs taken under solid-phase grinding conditions of 60% humidity for 3–10 minutes, showing the results of grinding amino acids without phenolic hydroxyl groups, highly hydrophobic amino acids, heteropoly acids, and liquid metal. The images show that amino acids without phenolic hydroxyl groups (arginine (R), alanine (A), histidine (H), isoleucine (I), phenylalanine (F), tryptophan (W)) and highly hydrophobic 3-(2-naphthyl)-L-alanine, after being thoroughly ground sequentially with PW and liquid metal, remained as powders and did not form a binder.

[0041] Appendix Figure 3These are digital photographs of L-DOPA (with two phenolic hydroxyl groups), heteropoly acids, and liquid metal after grinding under solid-phase grinding conditions of 60% humidity for 3–10 minutes. The images show that L-DOPA, heteropoly acids, and liquid metal formed a black adhesive after grinding. These results illustrate the uniqueness of amino acids: the presence of phenolic hydroxyl groups and a certain degree of hydrophobicity are both essential.

[0042] (3) Rheological behavior and shear tensile strength measurement of conductive adhesive under different solid-phase grinding times (grinding time of 3-10 minutes):

[0043] Rheological behavior: Under room temperature conditions, the prepared conductive adhesive PW / Y / LM was placed on a flat plate rheometer, and its storage modulus (G') and dissipation modulus (G”) were measured under conditions of 60% humidity and grinding for 3, 5, 7, 9, and 10 minutes, respectively. A flat plate sample holder with a diameter of 8 mm was selected, the sample thickness was set to 500 mm, the stress was set to 0.2%, the angular frequency scan range was 0.1 rad / s to 100 rad / s, and the frequency scan range was 0.1 Hz to 100 Hz.

[0044] Appendix Figure 4 This is a bar chart of the storage modulus of conductive adhesive PW / Y / LM under the conditions of 60% humidity and grinding for 3, 5, 7, 9 and 10 minutes respectively; as shown. Figure 5 As shown, the storage moduli of PW / Y / LM-2, PW / Y / LM-4, PW / Y / LM-6, PW / Y / LM-8, and PW / Y / LM-10 are 1.58, 2.86, 6.27, 19.67, and 46.47 MPa, respectively. It can be seen that the storage modulus of the conductive adhesive gradually increases with increasing grinding time, indicating that the cross-linking network density of the conductive adhesive becomes increasingly stronger.

[0045] Tensile shear strength: Two solid substrates (including glass, metal, polyetheretherketone, wood, etc.) with a width of 20 mm and a length of 90 mm are bonded together by overlapping with the prepared conductive adhesive PW / Y / Ag, wherein the bonding area is 4 cm². 2 The two ends of the bonded solid substrate were vertically fixed on an electronic universal testing machine and subjected to longitudinal tensile testing at a speed of 15 mm / min. The bonding area per unit area (m²) was measured at failure under a load parallel to the conductive adhesive PW / Y / LM layer, at 60% humidity and after grinding for 3, 5, 7, 9, and 10 minutes respectively. 2 The shear force (unit: N) that the conductive adhesive PW / Y / LM can withstand is evaluated by calculating the tensile shear strength at 60% humidity and after grinding for 3, 5, 7, 9 and 10 minutes respectively.

[0046] Appendix Figure 5The figures show the shear-tensile curves of the conductive adhesive PW / Y / LM after grinding for 3, 5, 7, 9, and 10 minutes, respectively. As the grinding time increases, the tensile shear bond strength of the titanium substrate gradually increases, reaching 366.23, 391.4, 454, 498, and 532 kPa. This indicates that electrostatic (proton transfer) is a kinetic process; as the solid-state grinding time increases, the Y and PW molecules pack more tightly, forming a denser cross-linked network, which in turn leads to curing.

[0047] Appendix Figure 6 These are the XPS curves of the conductive adhesive PW / Y / LM after grinding for 3, 5, 7, 9, and 10 minutes, respectively; as shown in the figure, in PW / Y / LM-3, corresponding to W... 5+ 4f 5 / 2 and W 5+ 4f 7 / 2 The reduced binding energy (at 37.3 and 35.6 eV) is very low, with a relative abundance of 16.24%. In PW / Y / LM-10, W... 5+ The relative content was 42.17%. This indicates that with increasing grinding time, the degree of charge transfer between PW and Y increases, and W... 5+ The relative content of Y and PW molecules increased. This further proves that during the solid-state polymerization process, as the grinding time increases, the proton transfer between PW and Y becomes more thorough, the degree of charge transfer increases, resulting in a tighter cross-linked network and thus the solidification phenomenon occurs.

[0048] (4) Conductivity of conductive adhesive under different solid-state grinding times (grinding time 3-10 minutes)

[0049] Conductive adhesive PW / Y / LM was coated into a polytetrafluoroethylene mold with dimensions of 12 mm in length, 6 mm in width, and 4 mm in height. Its conductivity was measured using a four-probe system at 60% humidity for 3, 5, 7, 9, and 10 minutes of grinding.

[0050] Appendix Figure 7 The conductivity data of conductive adhesives PW / Y / LM are shown in the figure, obtained under conditions of 60% humidity and grinding for 3, 5, 7, 9, and 10 minutes respectively. The figure shows that the conductivity of conductive adhesives PW / Y / LM is 0.04 S cm⁻¹. -1 ~0.08S cm -1 .

[0051] (5) Water-separable properties of viscous heteropolyacid conductive adhesives

[0052] At 60% humidity, a conductive adhesive prepared by solid-phase polymerization of aromatic amino acid Y containing phenolic hydroxyl groups, heteropoly acid PW, and conductive component LM was placed in a glass bottle containing 3-5 mL of deionized water. The conductive adhesive separated and detached.

[0053] Appendix Figure 8 This is a digital photograph of conductive adhesive placed in a glass bottle containing 3 mL of deionized water. The image shows that the conductive adhesive separates and debonds. This indicates that water can act as both a hydrogen donor and acceptor, gradually diffusing into the conductive adhesive and its interface, thereby simultaneously worsening both cohesive and adhesive interactions, ultimately leading to debonding.

[0054] Appendix Figure 9 These are reusable conductive adhesive digital photos. As you can see from the image, after absorbing a certain amount of moisture, they can be recycled and reused. The recycling process is simple, environmentally friendly, and reduces costs.

[0055] Example 2

[0056] As shown in Example 1, with other conditions remaining unchanged, 0.529g of PW(H3PW) was used. 12 O 40 The molecular weight (2880.05 g / mol) was changed to 0.336 g PMO (H3PMo). 12 O 40 Conductive adhesives with a three-dimensional structure (molecular weight 1825.25 g / mol) were prepared by solid-state polymerization. After grinding for 3, 5, 7, 9, and 10 minutes, the storage moduli of PMO / Y / LM-3, PMO / Y / LM-5, PMO / Y / LM-7, PMO / Y / LM-9, and PMO / Y / LM-10 were 1.28, 2.36, 6.27, 19.57, and 44.47 MPa, respectively; the tensile shear bond strengths of the titanium substrate were 362.23, 381.4, 434, 480, and 512 kPa, respectively, showing a gradually increasing trend.

[0057] This demonstrates that electrostatic (proton transfer) is a kinetic process. As solid-state grinding time increases, molecules pack more tightly, creating a denser cross-linked network, leading to curing. Furthermore, when the conductive adhesive is placed in a glass bottle containing 3 mL of deionized water, the adhesive separates and debonds. This indicates that water can act as both a hydrogen donor and acceptor, gradually diffusing into the conductive adhesive and its interface, thereby simultaneously worsening both cohesive and adhesive interactions, ultimately resulting in debonding.

[0058] Example 3

[0059] As shown in Example 1, with other conditions remaining unchanged, 0.529g of PW(H3PW) was used. 12 O 40 The molecular weight (2880.05 g / mol) was changed to 0.402 g HP2W 18 (HP2W 18A conductive adhesive with a three-dimensional structure was prepared using a solid-state polymerization strategy (molecular weight 4369.62 g / mol). The adhesive was ground for 3, 5, 7, 9, and 10 minutes respectively. 18 / Y / LM-3、HP2W 18 / Y / LM-5、HP2W 18 / Y / LM-7、HP2W 18 / Y / LM-9 and HP2W 18 The energy storage moduli of / Y / LM-10 are 1.68, 2.96, 6.37, 20.67 and 47.87 MPa, respectively; the tensile shear bond strengths of the titanium substrate are 368.23, 400.4, 455, 500 and 533 kPa, respectively, showing a gradually increasing trend.

[0060] This demonstrates that electrostatic (proton transfer) is a kinetic process. As solid-state grinding time increases, molecules pack more tightly, creating a denser cross-linked network, leading to curing. Furthermore, when the conductive adhesive is placed in a glass bottle containing 3 mL of deionized water, the adhesive separates and debonds. This indicates that water can act as both a hydrogen donor and acceptor, gradually diffusing into the conductive adhesive and its interface, thereby simultaneously worsening both cohesive and adhesive interactions, ultimately resulting in debonding.

[0061] Example 4

[0062] As shown in Example 1, with other conditions remaining unchanged, 0.529g of PW(H3PW) was used. 12 O 40 The molecular weight (2880.05 g / mol) was changed to 0.397 g SiW(H4SiW). 12 O 40 Conductive adhesives with a three-dimensional structure were prepared by solid-state polymerization using SiW (2878.17 g / mol). The storage moduli of SiW / Y / LM-3, SiW / Y / LM-5, SiW / Y / LM-7, SiW / Y / LM-9, and SiW / Y / LM-10 were 1.58, 2.56, 6.37, 19.87, and 45.87 MPa, respectively, after grinding for 3, 5, 7, 9, and 10 minutes. The tensile shear bond strengths of the titanium substrate were 367.23, 394.4, 444.6, 493.4, and 524 kPa, respectively, showing a gradually increasing trend.

[0063] This demonstrates that electrostatic (proton transfer) is a kinetic process. As solid-state grinding time increases, molecules pack more tightly, creating a denser cross-linked network, leading to curing. Furthermore, when the conductive adhesive is placed in a glass bottle containing 3 mL of deionized water, the adhesive separates and debonds. This indicates that water can act as both a hydrogen donor and acceptor, gradually diffusing into the conductive adhesive and its interface, thereby simultaneously worsening both cohesive and adhesive interactions, ultimately resulting in debonding.

[0064] Example 5

[0065] As shown in Example 1, with other conditions unchanged, 100 mg of tyrosine (molecular weight 181.18 g / mol) was replaced with 100 mg of levodopa (DOPA, molecular weight 197.19 g / mol), and a three-dimensional conductive adhesive was prepared using a solid-state polymerization strategy. After grinding for 3, 5, 7, 9, and 10 minutes, the storage moduli of PW / DOPA / LM-3, PW / DOPA / LM-5, PW / DOPA / LM-7, PW / DOPA / LM-9, and PW / DOPA / LM-10 were 1.88, 2.76, 6.87, 21.97, and 46.99 MPa, respectively; the tensile shear bond strengths of the titanium substrate were 374.43, 399.7, 448, 497, and 534 kPa, respectively, showing a gradually increasing trend.

[0066] This demonstrates that electrostatic (proton transfer) is a kinetic process. As solid-state grinding time increases, molecules pack more tightly, creating a denser cross-linked network, leading to curing. Furthermore, when the conductive adhesive is placed in a glass bottle containing 3 mL of deionized water, the adhesive separates and debonds. This indicates that water can act as both a hydrogen donor and acceptor, gradually diffusing into the conductive adhesive and its interface, thereby simultaneously worsening both cohesive and adhesive interactions, ultimately resulting in debonding.

[0067] Example 6

[0068] As shown in Example 1, with other conditions remaining unchanged, 0.529g of PW(H3PW) was used. 12 O 40 The molecular weight (2880.05 g / mol) was changed to 0.402 g HP2W 18 (HP2W 18 A conductive adhesive with a three-dimensional structure was prepared by solid-state polymerization using 100 mg of tyrosine (molecular weight 4369.62 g / mol) and 100 mg of levodopa (DOPA, molecular weight 197.19 g / mol). The tyrosine (molecular weight 181.18 g / mol) was replaced with 100 mg of levodopa (DOPA, molecular weight 197.19 g / mol). The adhesive was ground for 3, 5, 7, 9, and 10 minutes respectively using an HP2W... 18 / DOPA / LM-3、HP2W 18 / DOPA / LM-5、HP2W18 / DOPA / LM-7、HP2W 18 / DOPA / LM-9 and HP2W 18 The energy storage moduli of / DOPA / LM-10 are 2.88, 3.76, 7.87, 24.97 and 56.99 MPa, respectively; the tensile shear bond strengths of the titanium substrate are 379.43, 409.7, 468, 527 and 564 kPa, respectively, showing a gradually increasing trend.

[0069] This demonstrates that electrostatic (proton transfer) is a kinetic process. As solid-state grinding time increases, molecules pack more tightly, creating a denser cross-linked network, leading to curing. Furthermore, when the conductive adhesive is placed in a glass bottle containing 3 mL of deionized water, the adhesive separates and debonds. This indicates that water can act as both a hydrogen donor and acceptor, gradually diffusing into the conductive adhesive and its interface, thereby simultaneously worsening both cohesive and adhesive interactions, ultimately resulting in debonding.

[0070] Example 7

[0071] As shown in Example 1, with other conditions remaining unchanged, 0.529g of PW(H3PW) was used. 12 O 40 The molecular weight (2880.05 g / mol) was changed to 0.397 g SiW(H4SiW). 12 O 40 Conductive adhesives with a three-dimensional structure were prepared by solid-state polymerization using SiW (2878.17 g / mol) and 100 mg of tyrosine (molecular weight 181.18 g / mol), which were replaced with 100 mg of levodopa (DOPA, molecular weight 197.19 g / mol). After grinding for 3, 5, 7, 9, and 10 minutes, the storage moduli of SiW / DOPA / LM-3, SiW / DOPA / LM-5, SiW / DOPA / LM-7, SiW / DOPA / LM-9, and SiW / DOPA / LM-10 were 1.78, 2.76, 6.77, 21.87, and 46.87 MPa, respectively; the tensile shear bond strengths of the titanium substrate were 369.23, 399.4, 448.6, 497.4, and 526 kPa, respectively, showing a gradually increasing trend.

[0072] This demonstrates that electrostatic (proton transfer) is a kinetic process. As solid-state grinding time increases, molecules pack more tightly, creating a denser cross-linked network, leading to curing. Furthermore, when the conductive adhesive is placed in a glass bottle containing 3 mL of deionized water, the adhesive separates and debonds. This indicates that water can act as both a hydrogen donor and acceptor, gradually diffusing into the conductive adhesive and its interface, thereby simultaneously worsening both cohesive and adhesive interactions, ultimately resulting in debonding.

[0073] Example 8

[0074] As shown in Example 1, with other conditions remaining unchanged, 0.529g of PW(H3PW) was used. 12 O 40 The molecular weight (2880.05 g / mol) was changed to 0.336 g PMO (H3PMo). 12 O 40 The three-dimensional conductive adhesive was prepared by solid-state polymerization using 100 mg of levodopa (DOPA, molecular weight 197.19 g / mol) instead of 100 mg of tyrosine (molecular weight 1825.25 g / mol). 18 The energy storage moduli of / DOPA / LM-10 are 1.18, 2.36, 5.81, 17.61 and 44.81 MPa, respectively; the tensile shear bond strengths of the titanium substrate are 364.21, 384.1, 435, 481.1 and 515.1 kPa, respectively, showing a gradually increasing trend.

[0075] This demonstrates that electrostatic (proton transfer) is a kinetic process. As solid-state grinding time increases, molecules pack more tightly, creating a denser cross-linked network, leading to curing. Furthermore, when the conductive adhesive is placed in a glass bottle containing 3 mL of deionized water, the adhesive separates and debonds. This indicates that water can act as both a hydrogen donor and acceptor, gradually diffusing into the conductive adhesive and its interface, thereby simultaneously worsening both cohesive and adhesive interactions, ultimately resulting in debonding.

[0076] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A highly viscous, water-separable conductive adhesive, characterized in that, Composed of raw materials in the following mass ratio: H3PW 12 O 40 :Tyrosine :Liquid metal = 0.529 : 0.100 : 0.012; Or, H3PMo 12 O 40 :Tyrosine :Liquid metal = 0.336 : 0.100 : 0.012; Or, H6P2W 18 O 62 :Tyrosine :Liquid metal = 0.402 : 0.100 : 0.012; Or, H4SiW 12 O 40 :Tyrosine :Liquid metal = 0.397 : 0.100 : 0.012; Or, H3PW 12 O 40 :L-DOPA :Liquid metal = 0.529 : 0.100 : 0.012; Or, H6P2W 18 O 62 :L-DOPA :Liquid metal = 0.402 : 0.100 : 0.012; Or, H4SiW 12 O 40 :L-DOPA :Liquid metal = 0.397 : 0.100 : 0.012; Or, H3PMo 12 O 40 :L-DOPA:Liquid metal = 0.336:0.100:0.

012.

2. A method for preparing a highly viscous, water-separable conductive adhesive, characterized in that, Includes the following steps: (1) Weigh out each raw material according to the amount of the high viscosity, water-separable conductive adhesive as described in claim 1; (2) Mix and grind aromatic amino acids containing phenolic hydroxyl groups, heteropoly acids and conductive components for 3 to 5 minutes to form a conductive adhesive with low viscosity; (3) Continue grinding the mixture for 3 to 5 minutes to form a conductive adhesive with high viscosity.

3. The method for preparing a high-viscosity, water-separable conductive adhesive according to claim 2, characterized in that, Steps (2) and (3) are performed under conditions of 60% humidity.

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